Britain's Treasury has ordered the assets of five men frozen in connection with the alleged Iranian plot to assassinate Saudi Arabia's ambassador to the United States, officials said Tuesday.

Britain's finance ministry confirmed it has acted under the country's Terrorist Asset Freeze Act, making good on its pledge to take action against the five suspects. The action is in response to the alleged plot to kill Saudi Arabia's U.S. ambassador Adel Al-Jubeir, and bomb the Saudi and Israeli embassies in Washington, D.C.

U.S. officials have described the plot as bungled, but a serious operation attempted by Iran's elite foreign action unit, the Quds Force.

British Foreign Secretary William Hague told the House of Commons last week that the alleged plan "would appear to constitute a major escalation in Iran's sponsorship of terrorism outside its borders."

"We are in close touch with the U.S. authorities and will work to agree an to international response," Hague said.